Answer:
see explanation
Step-by-step explanation:
If 2 lines are perpendicular then the product of their slopes equals - 1
The equation of a line in slope- intercept form is
y = mx + c ( m is the slope and c the y- intercept )
Consider the given equations
3x - 4y = 12 ( subtract 3x from both sides )
- 4y = - 3x + 12 ( divide terms by - 4 )
y = 
x - 3 ← in slope- intercept form
with slope m =
3y = 12 - 4x = - 4x + 12 ( divide terms by 3 )
y = - 
x + 4 ← in slope- intercept form
with slope m = -
Then
× - = - 1
Since the product of their slopes = - 1 then the lines are perpendicular
7 hours + 6 hours + 6 hours
=19 hours
12 minutes + 46 minutes + 53 minutes
=111 minutes
=1 hour 51 minutes
19 hours + 1 hour and 51 minutes is 20 hours and 51 minutes. This is the total time.
Average time = total time/number of deliveries
(20 and 51/60) divided by 3
=6.95 hours
= 6 hours and 57 minutes
We subtract 32 and 24 from 1219 and we get the answer. 1219-32-24=1163. 1,163 books were left.
Check out the picture I've got the full explanations on there
Hope it's clear
